Island



2 Sheets-Sheet 1.

(N o Model.)

J. A. TRUE.

SEWING MACHINE.

Patented De. 13,18 8 l.

FIGHE FI 5.3i

INVENTD H N. PUERS, mnmmhognpher. wnshinglpn. D. c.

(No Model.) 2 sheets-sheet 2.v

J. A. TRUE.

SEWING MACHINE.

No. 250,689. Patented 1360.13.188l'.

wrrNEssEs. INVENTUH.

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UNITED STATES Frise.

'PATENT JAMES A. TRUE, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO JOHN B.

ANTHONY, 0F SAME PLACE.

SEWING-MACHINE.

SPECIFICATION forming part of Letters Patent No. 250,689, dated December13, 1881.

Application filed August 18, 1881.

To all whom it may concern Be it known that I, JAMES A. TRUE, of thecity and county of Providence and State of Rhode Island, have invented anew and useful Improvement in Sewing Machines; and I do hereby declarethat the iollowingspecification, taken in connection with theaccompanying drawings, forming a part of the same, is a full, clear, andexact description thereof.

My invention relates to that variety of sewing-machines particularlyadapted for sewing soles upon boots and shoes, stitching leather, &c.,which forms a "lock-stitch7 and employs a shuttle located upon that sideof the work from which the needle approaches.

My improvement consists in the mechanism employed for controlling themain or spool threads during the formation of a stitch, and in means forlocating the position of the lock of the threads in the goods.

In lock stitch sewingmachines so constructed that the main thread hasbeen drawn in to nish the stitch by the rising needle, and

in that class of machines particularly adapted to sew leather, &c.,inwhich the shuttle is located upon that side of the work from which theneedle approaches and the thread has been drawn in to nish a stitchduring and by the operation of forming the initial portion or loop ofthe subsequent stitch, an undue strain upon the thread has been producedas it passes through the needle-eye and is sharply bent around the same,causing the thread to be badly chafed and ofttimes to be broken.

The main object of my invention is to remedy this defect, and this Iaccomplish by nishing the stitch independently of the needle and beforea subsequent stitch is commenced, as will hereinafter appear.

Referring to the drawings, Figure l represents, in front elevation, aportion of a machine embodying my improvement. Fig. 2 shows a section otFig.- l on line ww. Fig. 3 repre sents a section of Fig. 2 on line y y.Figs. 4, 5, and 6show a stitch in various stages of formation, and Figs.7 S, 9, and l1 represent certain parts of the machine in detail. Fig. 10shows in side elevation a portion of a machine embodying my improvement.

In the drawings only such portions of the (No model.)

machine are shown as are necessary to an understanding oftheimprovement.

A is the horn or bed adapted to support the work, and commonly used inbottoming boots and shoes.

B is the needle, secured in the needle-bar B', to which verticalreciprocating motions are given by the usual mechanism in such wellknownmachines.

C is the hook-shuttle, mounted in a holder, C', and arranged to revolvein a horizontal plane at the proper time and pass the thread which itcarries throughvthe loop formed in the under or spool thread.

D is the spool which supplies the main or under thread.- Itis mounted ona standard secured to the base-member A' of the horn. The thread passesfrom the spool D to a drumwhel, E, which is loosely mounted to revolveupon a spindle, E', Figs. l, 2, 3, 7, and l1, except When it is lockedagainst rotation, as hereinafter described.

Between the,spool D and the drum-wheel E is a roller, F, which ismounted on an arm, F', and presses the thread against the wheel by theaction of a spring, f, as shown in Figs. l and 3, and constitutes aspring-clamp to press the thread against the surface of the drum inorder to create a considerable extent of frictional contact between thethread and the drum. This spring-clampFalso serves to give a slighttension to the thread, to prevent slipping, and dispenses with thenecessity of Wrapping the thread one or more times around the drum forthat purpose. From the roller F the thread passes nearly around thedrum-wheel E, then around a roller, G, which is located considerablyabove the horizontal diameter of the drum E, and on a vibrating arm, G',which is mounted upon the spindle E', so that when said arm is vibrated,as hereinafter described, the said thread-roller guide G will move in apath concentric with the periphery of the drum E. From said roller G thethread passes through a slotted guide-eye, g, overlying thev roller G,and concentric'therewith, as shown in Figs. 8 and 9, onward around apulley, a, then upward and out through the end of the horn A, as shownin Fig.1.

To the hub of the arm G' is attached a seg mental gear, y', Figs. l, 2,and 3, which meshes with a segmental rack, h, upon a lever, H, pivotedto the base-member A' of the horn, as shown in Fig. l. The arm G', withits roller G, is partially rotated in opposite directions upon thespindle E' by the upward and downward movements of the rack end ot' thelever H. These movements are imparted to the lever through avertically-sliding rod, J, pivoted thereto, as shown in Fig. l, by alever, K, which is pivoted to a sleeve, 7c, mounted on the rod J,between a shoulder or nut, j, and a nut, j'. The lever K is actuated bya cam, K', upon a vertical shaft, K2, which shaft is driven by bevelgears from a pulley, K3, mounted on the Idriving-shaft ofthe machine, asshown in Fig. 10.

Suppose the machine to be in operation and a stitch about to becommenced, the needle will be at its lowest point, as shown in Fig. 4,and the roller G will be in its rearward position-that is, near theroller F, as shown by dotted lines in Fig. l. By mechanism wellknowu inthis variety of machines the under thread is now partially wound aroundthe needle, so that when the latter rises its hooked end will engage thethread and carry it upward to form the loop through which the shuttle isto pass. When the needle commences to rise, and during the greaterportion of its upward movement, the arm G', with its roller G, is movedtoward the horn A by the downward motion of the lever H, and delivers tothe needle, as required, the exact amountof thread which is enteringinto the loop. No thread passes from the spool at this time, assufticent thread to form the greater portion of the loop is given off bythe swinging arm G' and its roller G. To guard against any rotation ot'the spool by the pull of the needle when it is rising to form thisportion ofthe loop, the wheel E is firmly clamped, to prevent itsrotation by a tooth, l, on an arm, L, which arm is pivoted to the baseA'. This tooth occupies a groove, e, in the side of the wheel E, Figs.3, 7, and 11, and is brought into engagement with the outer wall of thegroove to clamp the wheel by a spring, L', Figs. 2, 3, and Il, whichconstantly acts to raise the outer end of the arm L. The friction ot'the thread upon the clamped wheel added to the pressure of the roller Fupon the thread prevents the rising needle from drawing thread from thespool. At some time during the rise of the needle, however, suflicientthread to form a stitch must be drawn from the spool.l As the machine isarranged this is done as the needle approaches its highest point. Forthis purpose the drumwheel E is unclamped by the action uponv the freeend of the arm L of a pin or boss,`h', onl the lever H, Figs. 2, 3, and11. As the lever H descends the boss lo' comes in contact with the armL, depresses its free end, and moves the tooth Zoutv of engagement withthe wall of the groove e, leaving the drum-wheel E free to turn; and theneedle, during its continued rise, draws from the spool-withoutembarrassment-an amount of thread equivalent to that which is to enterinto the stitch, the said amount of thread entering into and completingthe loop. At or about the time the needle reaches its highest point afinger, m, on a vibrating arm, M, which is actuated by a cam y orequivalent mechanism, (not shown in the drawings,) is made to separatethe legs of the loop, as shown in Fig. l, as is common in machines ofthis class. The hooked end of the needle now descends into a perforationin the finger m. to clear itself of the thread, as shown in Fig. 5, andthe shuttle, now in revolution, enters the loop. The linger .m is nextwithdrawn by a downward and rearward movement, and the shuttle and itsthread pass through the loop, leaving the same standing up from thegoods. The stitch is now ready to be finished or drawn in. This isaccomplished independently of the action of the needle in forming thenext stitch by the arm G', which, as the shuttle clears the loop, ismoved rearward by the rising lever H of the second order, and draws theloop down toward the goods, as shown in Fig. 6. At the same time thedrum-wheel E is locked fast against rotation, because the rising of thelever H allows the spring L to cause the tooth Z on the arm L to engagethe drum-wheel E and clamp it, so that no thread can pass from the spoolduring the finishing of the stitch. Then the arm G' and its roller Greach their rearward position the stitch will be completedthat is, theunder and shuttle threads will both be drawn down into the goods by theaction of the arm G' on the under or spool thread,making alockstitch.

Preferably the lock of the stitch is located at or about a point midwaybetween the upper and under surfaces of the work; but as the workdiffers in thickness and character it is necessary that means beemployed whereby thc position ot' the lock of the threads can bedetermined at pleasure.

From the foregoing description it will be understood that the positionof the lock ofthe threads is determined by the movement of the arm G'and that this arm derives its motions from the lever K through the rod Jand lever H. According, therefore, to the length ot' time which thesleeve k, pivoted to the lever lK, engages the nut j' on the rod J whilesaid lever is in motion, the amount of the rearward movement ot' the armG' will be more or less in extent. The lower the nut 7" is adjusted onthe rod the greater will be the rearward movement of the arm G' and thedeeper will the lock of the threads be drawn into the goods, and thehigher the adjustment of the nut 7" the less will the arm G' moverearward and the nearer the upper surface of the work will the lock-ofthe threads be located. During the drawing in or nishing of the stitchthe needle-will descend, an'd when the arm G reaches its rearwardposition the work will be fed forward and the operations above describedwill be repeated to form subsequent stitches.

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The slotted guide-eye g is, as before stated, concentric with thethread-guide roller G. This construction is important for the reasonthat it enables the thread to be guided without being chafed in all thepositions which the roller G is obliged to take as the result of thevibration of the arm G'vwhen acting in combination with the thenstationary drumwheel E to complete the stitch.

To regulate the friction upon the drum E at the times when it isintended to revolve in allowing thread to be given off for sewing, asimple friction device, such as is represented in section at Fig. 2, isapplied to the hub of the drum.

What I claim as my invention, and desire to secure bytLetters Patent, is

1. The combination, substantially as set forth, of the drum-wheel E,around which the main thread passes, and which in the formation of astitch by the machine is firstfree to revolve to allow the thread to hegiven oft' and afterward locked to prevent its rotation, a vi hratingarm, G', mounted on the axle of the drum, carrying a roller or guide forthe thread, and a lever, H, for causing the said arm to be vibratedrearward over the periphery of the drum-wheel E while the latter islocked to prevent its rotation, whereby the under or main thread ispulled backward to fully complete the stitch inthe work.

2. The combination, substantially as set forth, of the drum E, aroundwhich the main thread passes, a spring locking device, L l, and thelever H, the upward and downward movements of which control said lockingdevice, so that at determined times the drum will be free to revolve togive off the thread and afterward be locked while the thread is beingdrawn backward to complete the stitch. K

3. The combination, substantially as set forth, of the drum E, thepressure-roller clamp F, and the vibrating arm G', carrying aguideroller for the thread, whereby the thread, when the drum E islocked against rotation, will, by frictional contact with the surface ofthe drum, be prevented from slipping thereon.

4. The combination, with the drum E, of the vibrating arm G', thethread-guide roller G, and the slotted guide-eye g, concentric with saidroller, substantially as and for the purposes specified.

5. The combination, substantially as set forth, of the lever H, thevibrating arm G', carrying a thread-guide roller, and suitable adjustingmeans, as described, for regulating the extent of movement of the leverH, and consequently the extent of vibration ot' the arm G', whereby theposition of the lock ot' the main and shuttle threads in the goods maybe determined.

JAMES A. TRUE.

Witnesses W. H. THURsToN, I. KNIGHT.

